Re: Inconsistent use of \ref and \eqref in ox-latex and ox-html

[Brian Powell]

Nicolas,

Thank you for the message. I spent about 2 hours on it today learning more 
about lisp and the internals to explain your email to me. I learned a lot.

I have modified ox-html.el to include a local OPTION as well as a customizable 
setting. I tested with both as well as with an export option. All three worked 
correctly. I also updated the org-manual.org.

Please find my patch attached.

Cheers,
Brian

equation-ref.diff
Description: Text Data

On Fri, Apr 17 2020, Nicolas Goaziou wrote:

> Hello,
>
> Brian Powell <address@hidden> writes:
>
>> The issue is that when exporting equation numbers with ox-html, it uses 
>> MathJax's \eqref that wraps the equation in parentheses, for example:
>>
>> "Refer to (3) for more."
>>
>> However, when exporting the same document with ox-latex, it uses Latex's 
>> \ref that does not wrap the equation in parentheses. Would it be possible to 
>> add an option or variable to ox-html for the user to select whether to use 
>> \ref or \eqref on export?
>>
>> For those of us that publish to HTML and PDF, it is very difficult because 
>> you end up with either double or no parentheses.
>>
>> My proposed fix would be a change to ox-html from:
>>
>>                (format "\\eqref{%s}"
>>                        (org-export-get-reference destination info))
>>
>> to
>>
>>                (format (if org-html-export-mathjax-ref "\\ref{%s}" 
>> "\\eqref{%s}")
>>                        (org-export-get-reference destination info))
>>
>> The variable org-html-export-mathjax-ref is non-nil to use \ref vs.
>> nil to be the default \eqref.
>
> The variable could be more general, e.g.,
> org-html-export-equation-reference-format, and default to "\\ref{%s}".
> Note the export back-ends do not use variables directly. It would be
>
>   (format (plist-get info :html-equation-reference-format)
>           (org-export-get-reference destination info))
>
> where the correspondence between :html-equation-reference-format is set
> in back-end definition.
>
> Also, it needs to be referenced in "HTML specific properties" section of
> the manual.
>
> Would you want to propose a patch ?
>
> Regards,